Midterm 1 - UNIT 04 Flashcards
What is a carb? = Types of dietary carbs 1 2 3
= ‘hydrate of a carbon’ - manufactured by plants
1 Sugars
2 Starch
3 Fibre
1) SUGARS 3 types: 1 ex 2 ex 3 ex
1 Monosaccharides: simplest form - 3to9 C atoms (Glucose, Fructose, Galactose)
2 Disaccharides: 2 monosacc - chemically bound
(Lactose, Maltose, Sucrose)
3 Sugar alcohols: manufactured - derived from monosacc - used as sweetener
2) STARCH = Animals vs Plants P: 1 P: 2
= storage form of glucose
A: glycogen
P: starch & fibre
1 Amylose: curled - makes up 1/4 of starch in food —LESS bioavailable
2 Amylopectin: straight chain- makes up 3/4 starch in food - branch - MORE bioavailable
2 Amylopectin
3) FIBRE = 2 types: 1 function: ex 2
= Non-digestible carbs (in plants)
- complex carb
1 Soluble fibre
- dissolves in hot water - forms a gel
- SLOWS gastric motility
- FULLER feeling
- absorbs FA (lymph doesn’t)
- decreases Cholesterol/CV disease
- ex: oat, bran, dried beans
2
function:
ex
2 Insoluble Fibre
= doesn’t dissolve in hot water
- absorbs water into GI system
- speeds up intestinal motility / decreases absorption time
- decreases chance of type 2 DM
- too much insoluble –> nutr deficiencies
- ex: fruit skins, veggies
Path of consumed carbs through the body:
4 steps
1 Starts @ mouth - amylase from salivary glands
2 monosaccharides = end product of carb digestion –> enter capillaries of intestinal villi
3 Monosacc travel to liver VIA hepatic portal vein
4 In liver, galactose and fructose are converted to glucose then glucose to storage (most not all)
WHY do we need carbs?
(1-3)
1
fuel source for ____
2
3
1 Energy Needs
for neurons (ONLY uses glucose) - can used ketones
- RBCs only use glucose
- need carbs to metabolize other fuels
2 Pregnancy
- placenta and fetus only feed off glucose
3 Spares muscle protein degradation for energy
- glucose must be synthesized from muscle protein (if body doesn’t have enough carbs - liver will break down muscle)
- AA converted to 1 ketone bodies 2 FA 3 glucose (if muscle protein is broken down)
CARBS & Energy
- we store glucose as what in where
- what has higher conc
- which has higher total energy
- as glycogen in liver and skeletal muscle cells
- LIVER has higher conc
- MUSCLE has higher overall energy as there is more space - more muscle
Physiological pathway of glucose molecules after a meal is consumed
1-7
(1-3)
1 when person eats - blood gluc rises
Carbs go thru mechanical and chem digestion to intestines and absorbed into bloodstream and circulated
2 high blood glucose gets stimulates — pancreas to release INSULIN in the blood—
[endocrine organ - produces insulin and glucagon and hormones enter blood to perform their function]
- Insulin detects extra glucose molecules - when insulin is in the blood it will go to target cells (liver and muscle) to trigger them to uptake glucose for storage
3 Insulin stimulates the uptake and storage as glycogen and stimulates the conversion of excess glucose into fat for storage
(4-7)
4 as the body uses glucose - levels decline in the blood- pancreas will detect the drop
5 low blood glucose stimulates pancreas release of glucagon –> blood
[specifically targets the LIVER not muscle]
6 Glucagon stimulates the liver to breakdown stored glycogen and release glucose into the bloo
7 blood glucose beings to rise to restore healthy levels (not to after meal levels)
GLYCEMIC INDEX = 2 standards: factors affecting GI of foods: 1 = ex 2 - concern with consuming high GI foods... 3 ex
= a measure (no units) of the potential of food to raise blood glucose levels
- how quickly blood glucose rises after a meal
: 1 slice of white bread or pure glucose
1 Proportion of carb content of ingested food
[more carb higher GI]
ex - ice cream = 61 GI
boiled potato = 85 GI
2 Type of carb simple (sugar) - increases GI complex starch - decreases GI as it stays in GI tract longer
… plays an indirect role with fat storage - insulin promotes glucose from blood–> storage - fat promotion effect
3 Cooking
- heat helps to disrupt chemical bonds
- faster digestion
pasta boiled 5 min = 34
boiled 10 min = 40
GLYCEMIC LOAD
= (eqn)
ex
= GI x amount of available carbs in food source / 100
- how HIGH blood glucose gets
- predictor of developing type 2 DM & CV disease
ex: corn muffin
GI = 102 carbs = 29 g = GL 30
Process of GLUT 1 and GLUT 4
embedded :
what happens when many glucose molecules appear…
= glucose transporter
: in the muscle fibre membrane to move glucose into muscle cytoplasm
- glucose moves through the blood, enters extra-cellular space - will bind to asparagine 45 - form a chemical bond THEN GLUT-1 transporter moves glucose into cytoplasm to store or use as fuel
WHEN MANY GLUC APPEAR…
this exceeds capacity of GLUT-1 therefore insulin will bind to specific protein receptor in muscle fibre mem to ACTIVATE enzymes of interior muscle fibre - GLUT-4 = same as GLUT-1 but insulin calls upon it
Pancreatic Hormones 1 produced by: function: overall effect: 2 produced by: function: - stimulates \_\_\_\_\_\_ = overall effect:
1 INSULIN
: beta cells of pancreas
: helps take in glucose from blood - target cells — stimulates liver and muscle to store as glycogen
: lowering blood glucose
2 GLUCAGON
: alpha cells of pancreas
: signals starved state - very low glucose levels— stimulates breakdown of glycogen from liver –> blood
- Gluconeogenesis = production of glucose from AA
: raises blood glucose levels
CARB - related disorders 1 Diabetes Mellitus = characterized by: results from:
Diabetes insipidus:
= a disorder of carb metabolism characterized by hyperglycemia & glycosuria - results from inadequate production or utilization of insulin
- more people affect by type 2
: impaired water re-absorption in kidney (lack of ADH or vasopressin)
